Automatic jack rafter bevel square



Aug. 5, 1%47.

P. F. WITTER AUTOMATIC JACK RAFTER BEVEL SQUARE' Filed June 26, 1945 INVENTOR PHILANDE]? I W] TTEB M f M ATTORNEY-S Patented Aug. 5, 1947 UNITED STATES-FATE? Claims;

An object of my invention is to provide an automatic jack rafter bevel square which is an improvement over my Patent No. 2,340,032, issued on January 25, 1944, for an automatic jack rafter bevel square. In the patent I show the device as comprising a body member adapted to be placed against the side of a jack rafter, the bodyhaving a head designed to rest on the rafter when the instrument is used. The body also has an arm pivotally secured thereto and a quadrant with an arcuate slot and a set screw for securing the arm to the quadrant in adjusted position.

In the present form of the invention, the arm is pivotally secured to the body of the instrument and has a link connection between itself and a carriage which is slidably connected to the body. Markings or calibrations on the body indicate the position of the carriage for holding the arm at the desired angle for marking a line on the jack rafter. The line shows the angle of cut to be made.

The present device is designed to be manufactured at less cost than the one shown in my patent and the body is formed of sheet metal that is shaped in a particular manner. The angle indicating arms are pivoted directly to the body. The entire device is designed to be stamped from sheet metal and the structure is such that the device is simple and will be strong and durable for the purpose intended.

Other objects and advantages will appear in the following specification, and the novel features of the device will be particularly pointed out in the appended claims.

My invention is illustrated in the accompanying drawings forming a part of this application, in which:

Figure 1 is a perspective view of the device shown applied to a jack rafter for the purpose of marking cutting lines on the top and side of the rafter;

Figure 2 is a plan view of the device showing the parts in folded position;

Figure 3 is a side elevation of Figure 2;

Figure 4 is an end elevation of Figure 2; and

Figure 5 is a schematic view illustrating a hip rafter with two jack rafters extending there- This body is preferably made of sheet metal and has inclined sides 1 and '2 that extend throughout the length of the body and cause the body to take the shape of a channel with obtusely inclined sides. The sides I and 2 have edges 3 and 4 that are coextensive therewith and are preferably beveled so that the edges will lie in a plane that parallels a plane coinciding with the central portion 5 of the body. The central portion is slotted at 6 and this slot extends throughout a substantial length of the body and is disposed midway between the sides I and 2.

An arm B is pivotally secured to the body and in actual practice th arm is formed from a strip of metal that is bent to form two parallel spaced portions 7 and 8 and these portions straddle and are pivotally secured to a lug ii by a pin it or other suitable supporting means. The lug 9 is carried by the body A. The two arm portions l and 8 are formed into a loop I l and this loop has a Width equal to that of the body and has ears or lugs 12 and it that project beyond the sides of the loop. The ears l2 and i3 take the place of the pin shown in my patent.

A link 14 is pivotally secured to the spaced parallel portions 1 and 8 of the arm B at i5 and the link is received between the parallel portions. A carriage C, see Figure 1, is slidable along the body A and a set screw It extends through the carriage and through the slot 6. The set screw has a head [1 bearing against the underside of the central portion 5 of the body. The carriage C has an integral sleeve l 8 through which the screw [6 slidably extends and a nut I9 is threaded upon the screw and is tightened for securing the carriage in adjustable position along the body A. Figure 1 shows the link It pivotally connected to the carriage C at 20.-

Figure 2 shows the body A calibrated at 2! for indicating where the carriage C is to be placed when the arm B is to extend at a predetermined angle with respect to the plane of the central portion 5. Figure 3 shows the left hand end of the carriage C beveled at 22 and the beveled edge is brought into registration with the desired calibration. For example, the calibration mark 6 stands for a six-inch rise and the calibration mark 12 stands for a twelve-inch rise for every twelveinch run.

I provide angle indicating arms D and E and these are pivoted tothe inclined sides i and 2 of the body A at 23 and M, respectively. Each arm has a projection adjacent to the pivot that extends at right angles to the length of the arm. Both Figures 2 and 4 show the arm D provided with a projection 25 and the arm E provided with a projection 26. Figure 4 illustrates the projections 25 and 28 as lying in a plane that passes through the edges 3 and 4 and that is parallel to the central portion 5. When the arms D and E are not used, they will extend along the inclined sides 1 and 2 and overlie them. The projections 25 and 2S constitute handles for initially swinging either arm into an angular positionwith respect to the body A.

From the foregoing description of the various parts of the device, the operation thereof may be readily understood.

In Figure 5 I indicate a hip rafter F and also show a right and left hand jack rafter G. It is necessary to make a side out on thejack rafter at 21 and a rise cut on the same rafter at 28-. Figure 1 illustrates a perspective view of the jack rafter G with the top of the rafter indicated at 29 and the side at 3! The carpenter determines what run and rise are desired and swingsthearm B until the carriage registerswith the desired calibration and then tightens thenut Either the arm D or the arm E is now swung into open position, this depending on whether a right or a'left hand rafter is to be cut. The device is placed on the jack rafter G in themanner shown in Figure 1. This figure showsthe arm E extended and resting on the top surface 29 of the jack rafter. The ear l3 of the arm B also rests on the top surface 23- and the edge e. of the inclined body side Z-bears against the side 3% of the jack rafter. r The instrument as shown in Figure 1 is set for marking the rise line 3! and this line will. extend at right angles to the rafter top- 29. In actual practice the line 3! will coincide with the edge e of the body since the edge will act as a guide for the marking instrument, but for the purpose of clarity, the line 3! is shown moved to the right of the body A in Figure 1. The arm E will extend at the desired angle across thev 110929 of the rafter and a side bevel line 3?. can be drawn on the surface 2%, using the arm E as pivotally secured to the body at 24, it will swing,

down to contact with the rafter: top 29 regardless of the angle assumed by the base A on the rafter side 35. It will be seen from. this that regardless of the angular position of the body A on the rafter side 38, the arm E (or the arm D) when brought into contact with the rafter top 29, will extend at the required angle across the top. a

The carpenter can draw two lineson'the rafters side and top corresponding'toy the angles made by the body A and the arm E and, then the rafter can be out along these two lines. The

out piece X is discarded and the cut end. of therafter will now fit the hip rafter F as indicated in Figure 5. When jack rafters on the opposite side of the hip rafter are to be cut, the arm D is used in place of the arm E. After the device has been used, it may be folded into a compact position as shown in Figures 2 and 3 and the device is small enough to be readily slipped into the pocket. When the arm D is used for marking purposes, the lug or ear !2 will rest on the top surface of the jack rafter. The arms D and E swing in planes that extend at angles of degrees with respect to the plane in which the arm B swings.

The calibrations 2| take into account that the device is to be supported on the rafter D by either one of the ears l2 or [3, and that the device is also supported by either one of the arms D or E.- The arm B will extend at an angle With respect to the rafter top when the device is used,

'but this angle has been taken into consideration. in the designing of the instrument, so that the body A and either one of the arms D or E will extend at the proper angle on the rafter when the arm, B has been set at the desired angle. When the arm B has been adjusted to the pitch of the roof and the device placed on the rafter, the arm D or arm E will, be self-adjusting and when swung into contact with the rafter top, it will indicate the desired side out angle: at which the rafter must be cut. The arm D or E automatically assumes the proper angle for the side out as soon a the arm is brought into contact with the top surface of the rafter.

The, device does away with the necessity of using a carpenters right angle square and figuring out the. desired angles from the numbers on the square. All mathematical figuring which the square requires to be accomplished by the person using it. is automatically accomplished by the mere placing of applicants instrument. on the rafter after the required setting of the arm B has been made.

The projection 25. or 26 can be used as a sup port for the instrument when the arms D and- E are closed and the device is used as a bevel square. For example, the arm E in Figure 1 can be swung into closed position and then the projection 26 can rest on the surface 29 to sup port the device. The body A will extend along the surface, 3% to indicate the desired bevel andthenthe line 3! can bemarked on the surface 3Q.

1. A jack rafter bevel square comprising an elongated body, an arm pivotally secured to the body and swingable in a plane that bisects the length of the body and is perpendicular thereto, means including an adjustable brace extending from the arm to the body for securing the arm in different angular positions, an abutment car ried by the outer end of the arm, and a second arm pivoted to the body and swingable in a plane that extends at an angle of 135 to the plane in which-the first arm swings, said abutment and second arm adapted to rest on a jack rafter in a position to permit the elongated body toli'e against the side of the rafter.

2. In a jack rafter bevel square, an elongated body having obtusely inclined sides that make angles of 135 to a plane bisecting the length of the body and extending perpendicular thereto, the ,free edges of the inclined. sides constituting ruling edges for guiding a pencil when marking a rafter, a pair of arms pivoted to the sides and swingable in planes paralleling the planes of the sides, and means including either one of the armsfor supporting the device on a rafter in a predetermined manner so that the body will indicate theangle of the rise cut to be made on the rafter side and the supporting arm will indicate the angle of the side bevel cut to be made on the rafter top.

3. A jack rafter bevel square comprising an,

elongated body, an arm pivotally mounted on the body and being swingable in a plane that parallels the body length and that is perpendicular to the body, a pair of laterally extending abutments carried by the outer end of the arm and designed to rest on a rafter top, a pair of arms pivoted to the body and either one of which when extended will act as a second support for the device, said pair of arms being swingable in planes that extend at right angles to each other and at angles of 135 to the plane of the firstnamed arm, a carriage slidably mounted on the body, a link connecting the carriage with the first-named arm, means for securing the carriage to the body in adjusted position for holding the first-named arm at the desired angular position with respect to the body, said body having calibrations placed in the path of the carriage for indicating various rafter pitches, whereby a placing of the device on a rafter so that one of the abutments and one of the pair of arms will be supported by the rafter top, will dispose the body against the rafter side so that the rafter can be marked along the body side and supporting arm for indicating the proper angles for the rise cut and side bevel cut on the rafter.

4. In a jack rafter bevel square, an elongated body made of sheet metal and having obtusely inclined sides that make angles of 135 to a plane bisecting the length of the body and extending perpendicularly above the body top, a pair of arms, each one being pivotally secured to a side and swingable in a plane paralleling the side, a third arm pivoted to the body and swingfree end of the third arm having laterally projecting abutments, said body being longitudinally slotted, a carriage slidable along the slot, a link pivotally connecting the third arm with the carriage, and means for securing the carriage to the body, said body having calibrations for indicating where to position the carriage for holding the third arm at the desired angle.

5. In a jack rafter bevel square, an elongated body made of sheet metal and having obtusely inclined sides that make angles of to a plane bisecting the length of the body and extending perpendicularly above the body top, a pair of arms, each one being pivotally secured to a side and swingable in a plane paralleling the side, an arm pivoted to the body and swingable in the perpendicularly extending plane, the free end of the last-named arm having laterally projecting abutments, said body being longitudinally slotted, a carriage slidable along the slot, a link pivotally connecting the second arm with the carriage, and means for securing the carriage to the body, said body having calibrations for indicating where to position the carriage for holding the second arm at the desired angle, said pair of arms having a laterally extending projection disposed adjacent to the pivot connection made between the arm and the inclined side.

PHILANDER. F. WITTER.

REFERENCES CITED UNITED STATES PATENTS Name Date Witter Jan. 25, 1944 Number 

